1. (a) Field
The present invention relates to a liquid crystal composition and a liquid crystal display. More particularly, the present invention relates to a liquid crystal composition improving response speed and a liquid crystal display including the same.
2. (b) Description of the Related Art
A liquid crystal display element is used in watches, electronic calculators, various home appliances, measurement devices, panels for vehicles, word processors, electronic schedulers, printers, computers, televisions, and the like. Typical liquid crystal display systems include a twisted nematic (“TN”) type, a super twisted nematic (“STN”) type, a dynamic optical scattering (“DS”) type, a guest and host (“GH”) type, an in-plane switching (“IPS”) type, an optically compensated birefringence (“OCB”) type, an electrically controlled birefringence (“ECB”) type, a vertical alignment (“VA”) type, a color super homeotropic (“CSH”) type, a ferroelectric liquid crystal (“FLH”) type, or the like. Further, multiplex driving is generally used in known static driving as a driving method, such that a simple matrix method and currently an active matrix (“AM”) method performing driving by a thin film transistor (“TFT”), a thin film diode (“TFD”), or the like are mainly used.
In the display methods, the IPS type, the ECB type, the VA type, the CSH type, or the like, are characterized in that a liquid crystal material having negative dielectric anisotropy (Δ∈) is used, unlike a current general TN type or STN type. Among the display methods, in particular the VA type of liquid crystal display, AM driving is used in a display element requiring a wide viewing angle.
Low voltage driving, a high speed response, and a wide operation temperature range are desired characteristics of the liquid crystal material used in the VA type liquid crystal display and the like. That is, dielectric anisotropy is negative, an absolute value is high, viscosity is low, and a nematic phase-isotropic liquid phase transition temperature (“Tni”) is high. Further, when setting Δn×d, in which Δn is a multiple of refractive anisotropy and d is a cell gap, the refractive anisotropy of the liquid crystal material needs to be controlled within an appropriate range so as to correspond to the cell gap. In addition, the cell gap of the display element may be small in order to implement a high speed response, but there is a limit in the reduction of the cell gap. It is useful when the liquid crystal composition having low viscosity is used in order to improve the response speed while the cell gap is not changed.
Three-dimensional (“3D”) stereoscopic image display devices have attracted attention with the development of the liquid crystal display technology. For displaying the 3D image, a pattern retarder type and a shutter glasses type of liquid crystal display system may be used. In the case of the shutter glasses, the left eye signal and the right eye signal are applied at a predetermined time creating a need for high speed driving.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known to a person of ordinary skill in the art.